1. Field of the Invention
The present invention generally relates to tire air pressure monitors and more specifically to a monitor for continuously indicating to a vehicle operator that each tire on the vehicle, including a spare, if present, is adequately inflated for safe xe2x80x9cover-the-roadxe2x80x9d operation. The invention also includes an indicator associated with each tire when the air pressure in any individual tire on the vehicle is not inflated to a pressure adequate for safe operation. The monitor includes a housing enclosing a pressure sensitive sensor, battery and radio frequency transmitter threadedly mounted on an outer threaded end of a conventional tire valve stem from which the Schrader valve element has been removed. The transmitter includes an antenna which extends into the interior of the tire for transmitting a signal to an indicator on the instrument panel or dashboard of the vehicle. The outer end of the housing has a conventional Schrader valve therein and the structure of the monitor enables air flow therethrough which permits inflation or deflation of the tire without removing the monitor. The signal transmitted from each transmitter to the receiver actuates only the indicator on the instrument panel associated with and receiving a signal from the transmitter monitoring the air pressure in the specific tire to which the indicator is assigned. The radio frequency transmitter and receiver enable a vehicle operator to observe an indicator for each tire so that the operator can determine whether each tire is adequately or inadequately inflated for safe operation of the vehicle.
2. Description of the Prior Art
The following U.S. patents, known to Applicant, disclose devices which relate to the invention disclosed in this application.
The prior art in this field of endeavor discloses various devices associated with the tire valves or tires of vehicles to provide an indication of air pressure in each vehicle tire. The prior art devices include pressure sensitive switch mechanisms in each tire valve or valve stem wired individually to indicators on the instrument panel of a vehicle. The prior art also discloses pressure sensitive switches associated with vehicle tires to actuate a transmitter which transmits a wireless signal to an antenna on the vehicle associated with an indicator on the instrument panel or dashboard of the vehicle to indicate to the vehicle operator that a particular tire has an inadequate air pressure for safe operation of the vehicle.
The prior art does not disclose a monitor including a housing for a sensor, a transmitter and battery positioned therein with the housing being threadedly mounted on a tire inflation valve or valve stem from which the Schrader valve has been removed. The prior art also does not disclose a tire air pressure monitor in which the housing attached to the tire valve includes a Schrader valve in the outer end thereof with the components within the housing being constructed so that air can flow therethrough to enable inflation or deflation of the tire without removing the monitor. Additionally, the prior art does not disclose a transmitter having an antenna within the tire for wireless transmission of a radio frequency signal assigned to a particular tire to a receiver located within the cab of the vehicle and connected to an indicator actuated only by the transmitter in the tire to which a particular indicator is assigned to indicate whether the tire is either adequately inflated or inadequately inflated for safe operation of the vehicle.
The vehicle tire air pressure monitor of the present invention provides the operator of the vehicle with a separate continuous signal related to each tire on the vehicle, including a spare if present. Specifically, the monitor signals the operator whether each tire is adequately inflated for safe operation or each tire has an inflation pressure inadequate for safe operation of the vehicle. The monitor for each tire includes a pressure sensitive sensor, battery and transmitter utilizing radio frequency technology for wireless transmission of a signal to an indicator located within the cab of a vehicle for observation by the vehicle operator to indicate the inflation condition of each tire. The number of transmitters and indicators is the same as the number of tires on the vehicle. The indicators observable by the vehicle operator are associated with the monitor transmitters on the wheels on the vehicle thereby enabling the vehicle operator to receive an immediate warning when an indicator changes from indicating a safe operating air pressure in the tire to an unsafe air pressure in the tire with which the indicator is associated.
Accordingly, an object of the present invention is to provide a vehicle tire air pressure monitor for independently monitoring the air pressure in each tire on the vehicle and transmitting this information to receivers in the vehicle cab to actuate visual indicators thereby enabling an operator of the vehicle to immediately determine whether air pressure in each tire is adequate or inadequate for safe operation of the vehicle.
Another object of the present invention is to provide a monitor in accordance with the preceding object in which each transmitter is associated with a sensor and battery within the interior of a housing threadedly mounted on the outer end of an inflation valve for the vehicle tire. The transmitter includes a flexible antenna which extends into the interior of the tire to enable transmission of a radio frequency signal without interference from the tire rim or wheel.
A further object of the present invention is to provide a monitor for vehicular tire air pressure in accordance with the preceding objects in which the indicators observable by a vehicle operator are mounted in the instrument panel or dashboard of the vehicle with each indicator being assigned to and receiving transmitted radio frequency signals from one particular tire with the indicators including a green light indicating safe operating pressure of the tire and a red light indicating low and unsafe air pressure in the tire.
Still another object of the present invention is to provide a monitor for vehicle tire air pressure in accordance with the preceding objects in which the radio frequency transmitter and receiver utilize frequencies having characteristics in which the wireless transmitted signals are insufficient to cause interference with other radio frequency signals oriented externally of the vehicle on which the monitor is mounted.
Yet another object of this invention to be specifically enumerated herein is to provide a vehicle tire air pressure monitor in accordance with the preceding objects and which will conform to conventional forms of manufacture, be of simple construction and easy to use so as to provide a device that will be economically feasible, long lasting and relatively trouble free in operation.
These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.